The present invention relates to volume dosing devices or pumps, and more particularly such volume dosing devices whch are of the type used in connection with packaging machinery for filling a certain package or container with a predetermined volume of filling goods or material.
Volume dosing devices for filling of containers with a predetermined volume of material are generally known. Many of these prior art devices have only been capable of maintaining the desired exactness of a measured dose for a short period of time, after which the volume of the dose dispensed diverges more and more from stipulated tolerances. Some known solutions to this problem in the past have been to provide an adjustment, to a limited extent, of the positioning of the piston on the piston rod to thereby adjust the displacement stroke of the piston in the piston cylinder of the dosing device. However, such arrangements have not been capable of adjusting the volume to a large extent such as when the filling volume for different types of containers to be served by the dosing device deviates considerably. Rather, in those instances, it has been necessary to replace or alternately to adjust one or several elements in the force transmission mechanism of the piston.
While such arrangements may have been capable of providing an adjustable maximum exact dosing for the dosing device, these known solutions have not been very appealing since the adjustment requires a rather considerable manipulation and complexity, especially if the filler mechanism is to be adjusted to accommodate largely deviating filling volumes. Further, with such devices, in addition to being inconvenient in terms of adjustment, the accuracy of the measured dose to be dispensed is not always assured especially in light of uncontrollable and increasing play in the transmission mechanism after a certain time of operation. Consequently, there exists a need for an improved adjustable volume dosing device which utilizes a minimum of complex mechanism for accomplishing such adjustment.